Rotary Evaporation to Remove Solvent

Source: Dr. Melanie Pribisko Yen and Grace Tang — California Institute of Technology

Rotary evaporation is a technique most commonly used in organic chemistry to remove a solvent from a higher-boiling point compound of interest. The rotary evaporator, or "rotovap", was invented in 1950 by the chemist Lyman C. Craig. The primary use of a rotovap is to dry and purify samples for downstream applications. Its speed and ability to handle large volumes of solvent make rotary evaporation a preferred method of solvent removal in many laboratories, especially in instances involving low boiling point solvents.

1. Setup

1. Pour the mixture of solvent and desired compound in a round bottom flask. Best results are achieved when the flask is filled less than half full of the solution.
2. Fill the rotovap cold traps with dry ice.
3. Attach a glass "bump trap" which prevents any solution from entering the main part of the rotovap. Secure with a Keck clip.
4. With a Keck clip attach the flask and bump trap to the adapter portion of the roto-evaporator.
5. Lower the flask into the

Rotary evaporation can be used to separate solvent from many organic, inorganic, and polymeric materials. It is crucial that the desired compound has a lower boiling point than the solvent and that the compound does not form an azeotrope with the solvent. If these conditions are true, rotary evaporation may be a very efficient technique to separate solvent from the compound of interest. Lower boiling solvents work best, however, rotary evaporation is commonly used to remove water. Higher boiling solvents such as DMF and DMSO are more easily